The Plant Breeding
and Genetics division undertakes research on aspects of varietal
improvement and fundamental investigations in taxonomy, genetics,
cytogenetics, induced mutagenesis and morphogenesis. Collection,
maintenance and evaluation of germplasm was one of the activities
of this division till a separate division of Genetic Resources
was formed in 1983.

PRE-SEMI-DWARF
ERA

Until early 1950s,
varietal improvement was mainly restricted to pure-line selection.
The Working Party Meetings of the International Rice Commission
identified the drawbacks responsible for poor yield in local
cultivars such as late maturity, poor response to fertilizers,
proneness to stem collapse leading to lodging, susceptibility to
prevailing insect pests (stem borers and gall midge) and diseases
(blast and brown spot) and abiotic stresses caused by drought,
flooding and salinity and narrow range of adaptation. Following
this, the indica-japonica hybridization programmes - one
sponsored by the Food and Agricultural Organization and the other
by the ICAR were launched in 1952 at CRRI, Cuttack for the
benefit of the countries in tropical Asia and another in 1965 for
different rice-growing states in India, respectively. This
programme, however, brought limited success. From the crossed
seeds sent from CRRI to different countries and Institutions
within India, Regional Research Station (Tamil Nadu Rice Research
Institute), Tamil Nadu (Madras State) identified a promising
culture and released it as ADT 27. In addition, Mahsuri and
Malinja in Malaysia and Circna in Australia identified from this
programme were released for cultivation.

Recognizing stem
collapse leading to lodging in local cultivars as one of the
major limitations in restricting their yielding ability, the
institute took up breeding for non-lodging types using the stiff-strawed
javanica in early sixties. This resulted in the
development of CR 1014, a super fine grain variety capable of
yielding 3 to 4 t/ha under stagnant water conditions in
intermediate depth (0-50 cm) from a cross between T 90 and Urang
Urangan in early sixties. This variety became popular with the
farmers in the states of Orissa, Andhra Pradesh and West Bengal
and is being preferred by them even to-day. However, this variety
was released formally only in 1988.

SEMI-DWARF
ERA

Varietal
improvement

Varietal
improvement programme of the Institute took a new turn with the
introduction of high-yielding, semi-dwarf, photo-insensitive
varieties, Taichung (Native) 1 in 1965 and IR 8 in 1966 from the
Philippines to develop short-statured photo-insensitive varieties
capable of responding to high levels of nitrogenous fertilizers
thereby possessing remarkably high yield potential. The changed
scenario in rice cultivation characterized by new threats posed
by severe incidence of diseases and insect pests hitherto
considered minor in importance such as bacterial blight and
tungro virus complex, leaf and planthoppers and leaffolders and
resistance from consumers to accept the coarse grain types
necessitated incorporation of resistance to these insect pests
and diseases and consumer-preferred medium-slender and long-slender
grains in the newly bred varieties.

Varieties
for irrigated lands

At this period of
time, the concentration was to develop varieties suitable for
homogenous, relatively risk-free irrigated ecosystem. The
following 21 varieties developed by CRRI were released for this
ecosystem : Padma, Ratna, Krishna, Vijaya, Vani, Saket 4, Sarasa,
Supriya, Jayanthi, Kalinga I, Kalinga II, Kiran, Pallavi, Shakti,
Indira, Udaya, Kshira, Ramakrishna, Shaktiman, CR 138-928, and
IET 7280.

Till recently,
varieties suitable for the ecologically handicapped, rainfed
ecosystems, very diverse in nature and associated with high
degree of risk for rice cultivation, predominant in eastern India
were not available. As a result of increased attention in recent
years to develop varieties suitable for each of these harsh
environments, 12 varieties for rainfed uplands and 15 for rainfed
lowlands, developed at CRRI (listed below) were released for
cultivation.

Besides these
released varieties, a number of promising cultures (listed below)
suitable for different ecosystems with different durations have
been developed.

Situation
Varieties Duration Yield

(days) poten-
tial

(t/ha)

Rainfed upland CR
544-1-1 65-80 3.0-4.5

CR 544-1-3-4

RR 139-1 95-100 3.0-4.0

CR 628-2 90-120 4.0-5.0

CR 666-100

CR 142-3-8

Irrigated land CR
333-6-1 120-140 4.0-6.0

CR 308-408

CR 603-1-14-1

CRM 40

Rainfed lowland CR
95-26-1 Flowering 4.0

Shallow CR 210-1006
Oct 3-4th wk

(0-30) CR 210-1010

Intermediate

(0-50 cm) CR 629-243
Flowering 4.0

CR 629-256 Oct 3rd-

Nov 1st wk

Coastal saline CR
644 Flowering

areas (up to 50 cm)
Oct 3-4th wk 4.0-5.0

Varieties like
Ratna and Saket 4 (sister line of Ratna) in the early group and
CR 1014 in the late group are still extremely popular in many
parts of the country for the past 25 and 30 years, respectively.
Ratna and Saket 4 are popular in rice-wheat cropping system in
northern states and as summer crop in eastern states, while CR
1014 is popular for its good grain quality and suitability for
waterlogged areas.

Basic studies

Origin of
cultivated rice

Concerted effort
was made to trace the origin of cultivated rice from its wild
progenitors. It is generally agreed that the cultivated rice Oryza
sativa L. originated in Asia and O. glaberrima Steud
originated in Africa. The widely distributed, long-ligulated,
long-anthered perennial species designated as O. perennis
Moench was established as the ancestral species. The collection
of species from various countries showed a wide range of
variation, and it is possible that the cultivated rices might
have originated by hybridization between such taxa followed by
selection. It was also inferred that subspecies formation in O.
sativa was interconnected with geographical differentiation
of the ancestral species. The role of introgressive hybridization
in the origin of cultivated rices was highlighted through
critical studies carried out with collection from the Jeypore
tract which is considered to be one of the secondary centres of
origin of cultivated rices.

Genetics

Exhaustive studies
were conducted on inheritance patterns of morphological traits
such as plant stature, leaf characters, grain types and
pigmentation in different plant parts and information on the
number of genes governing these traits and their position in
linkage groups has been generated. In addition, inheritance of
quantitative traits related to yield and yield attributing
characters and their association was examined under different
situations which facilitate in enhancing the selection efficiency.

Inheritance
patterns and identification of genes for major diseases like
blast and bacterial leaf blight and insects such as stem borer,
gall midge and planthoppers have been investigated which resulted
in the identification of suitable donors. These donors have been
utilized in breeding programmes.

Induced
mutagenesis

Cultivars such as
T 141, Ptb 10, Saturn and Tainan 3 and the wild rices (spontaneas)
were subjected to treatments with chemical mutagens. Subsequently,
a few more tall indicas were also used. The result
indicated that mutagens, EMS, NMU and DES were potent enough to
induce a wide range of morphological and physiological variations.
The highest frequency of variants were the dwarfs and short culm
mutants. A large number of morphological mutants isolated were
studied for their genetics and breeding behaviour. Many of the
short culm mutants were characterized by stiff straw and longer
panicle and high tiller numbers, and consequently were proved to
have high yield potential. The dwarfing genes in these short culm
mutants were different from those found in Taichung Native 1,
thereby offering an alternate source of dwarfing gene in
hybridization programme. Several new mutant loci were studied and
genetics of some, such as gaping spikelets, zebra, striping,
beaked palea, palealess and nude panicle have been reported.
Experience with wild rices indicated that chemical mutagens can
successfully be utilized in selective elimination of undesirable
characters like awning, shattering and red pericarp in wild rices
thereby making them mutable for using the wild genotypes in
hybridization programme.

Induced mutation
as a tool for varietal improvement undertaken in the institute,
yielded four varieties, Sattari for rainfed uplands, Indira for
irigated lands, Padmini for shallow water regime with superfine
grain quality and Lunisree with long slender grain for coastal
saline areas where salinity and waterlogging coexist. Besides, a
productive mutant CRM 8 with aroma and cooking quality similar to
Basmati 370 and CRM 30 was evolved. Employing chemical mutagens,
it was also possible to remove the undesirable characters in wild
rices prior to their use in hybridization programme.

Development of
blast tolerant mutants from IR 50

Three blast
tolerant lines, CRM 49, CRM 51 and CRM 53 were developed from IR
50, a blast susceptible variety utilizing mutation breeding (chemical
mutagenesis) technique. Of the three lines, CRM 49 and CRM 51
were isolated from sodium azide-treated populations, while CRM 53
was developed from ethyl methane sulfonate (EMS)-treated
populations. The three cultures possess semi-dwarf stature, long
slender grains and an yield potential of 5 t/ha. These cultures
were evaluated for their blast tolerance at Hazaribag (Bihar),
Hyderabad and Maruteru (Andhra Pradesh), Jagadalpur (Madhya
Pradesh) and at Cuttack (Orissa). These cultures have performed
well in yield evaluation trials conducted in Assam and has been
proposed for release in that state.

Aneuploid

Two complete sets
of simple primary trisomics (2n + 1 = 25) were established in indica
varieties, Sona and Ratnagiri. Employing the primary
trisomics, a number of genes have been assigned to specific
chromosomes and linkage groups.

Detailed
anatomical studies of the genus Oryza and comparative
anatomical sutdy of high yielding varieties versus traditional
rice varieties revealed the development of better mechanical and
conductive tissues in semi-dwarf high yielding types.

Inter-relationship
of Oryza species was established based on size and
arrangement of cuticular papilae and marginal hairs of the leaf
blade. Two genes, Esb-a, Esb-b governing anatomical
characters with complimentary reaction for the extra-sclerenchymatous
band in flood tolerant variety FR 13-A and Fc for suscoid cells
in the leaf blade in a cold tolerant variety Ch 1039 with simple
inheritance pattern were identified.

Use of
alternate sources of dwarfism

To avoid narrowing
of genetic variability resulting in enhanced genetic
vulnerability, search for alternate dwarfing gene for utilization
was undertaken. Pankaj, sister line of IR 5, and Waikyaku, an indica
from main land China were identified as alternate dwarf gene.
These have been used for developing semi-tall high yielding
varieties such as Savitri (Ponmani), Gayatri, Dharitri (Pankaj x
Jagannath crosses) for shallow water ecosystem and Annada (MTU 15
x Waikyaku cross) for uplands.

A local land race
named KO with semi-tall plant stature, collected from Koraput
district of Orissa was found to have a dwarfing gene non-allelic
to De-geo-Woo-gen.

Strategic
reserch

Hybrid rice

Work on hybrid
rice was initiated at CRRI since 1984 with an objective of
developing appropriate parental lines viz., cytoplasmic genetic
male sterile lines (CMS), their maintainers and restorers for
irrigated as well as shallow submergence condition.

Twenty-five stable
CMS limes (from WA, Kalinga I and O. perennis sources) and
a number of maintainers and effective restorers for the above CMS
lines have been developed. Among these, most promising ones are:
Sarasa A, Pusa 33A (WA), Annada A (WA), Kiran A (WA), Deepa A (WA),
Monipur A (WA), Moti A (WA), Krishna A(O. perennis), Krishna
A (Kalinga I) and Mirai (Kalinga I).

Eleven high
heterotic hybrids were developed for shallow submergence
condition which have an yield advantage of 1 t/ha over the checks,
Swarna and Vajram.

Shuttle
breeding

Shuttle breeding
approach for development of suitable varieties for rainfed
lowlands of eastern India (Rainfed Lowland Consortium) was
undertaken. This has resulted in the identification of three
specific photosensitive groups, flowering during first week of
October, third week of October and first week of November
suitable for different regions of Eastern India.

While FR 13-A was
found to have high degree of submergence tolerance at early
vegetative stage, local cultivars like Khajara and Dhusara from
Orissa were found to have submergence tolerance both at early and
late vegetative stages. These are better donors for developing
varieties for flood-prone lowlands where submergence occurs more
than once due to cycles of floods.

Rice
biotechnology

A programme on
biotechnology was initiated for using recombinant DNA technique
for increasing the efficiency of breeding programme, compressing
the breeding cycle and transfer of novel genes to the high
yielding varieties. Wide hybridization with special reference to
diversification of cytoplasm and use of alien genes for biotic
and abiotic resistance is also being attempted. Tissue culture
techniques such as embryo rescue, anther culture and ovule
culture have been standardized to achieve maximum efficiency in
wide cross programme.

A large number (>1500)
of recombinants from inter-varietal, inter-specific and heterotic
hybrid combinations were developed utilizing improved anther
culture techniques. The significant improvements to the protocols
include the use of: (i) potato-II medium in anther culture of indica
rices, (ii) optimal phytoharomone combination in both callus
induction (auxin : cytokinin in 4:1 ratio) and regeneration (NAA
: kinetin : BAP in 1:1:4 ratio, and (iii) use of supplements like
coconut water, casein hydrolysate and sliver nitrate.

A large number of
somaclones have been developed from several indica
genotypes of: (i) different duration groups (early, medium and
late), (ii) salt tolerant genotypes, and (iii) aromatic rices.
Wide variation was observed for all the agronomic characters and
higher levels of tolerance (score of 3-4) was observed for
tolerance to sheath blight in the somaclones of Annada.

Seed production

CRRI is one of the
breeder seed production centres for rice under National Seed
Project since 1976. The national requirement of rice breeder seed
production placed before the institute up till now was 63.28
tones. Against this demand, this centre had produced and
distributed 75.21 tones of breeder seeds of 21 rice varieties so
far to various seed agencies namely the National Seed Corporation,
State Farm Corporation, State Seed Corporations, State
Agriculture Departmental Farms,Agricultural Universities and
private agencies on the basis of allotments made by Deputy
Agriculture Commissioner (Seed), Government of India. The
Institute also produced and distributed 4.95 tones of nucleus
seeds of 62 varieties for production of breeder seeds.